Nice post! Companies working with PR and Commnunication tend to focus on influencers or opinion leaders as the ones to focus attention. That is from the perspective of understanding "change" as the outcome of encounters with people with certain capabilities. However, as Duncan Watts and many others have proved, these people tend to have limited influence beyond their own networks and groups. Instead, boundary spanners seem to be critical to create a larger impact on the market or within an organisation. So in a "Need-to-Share" situation we depend on the ones bridging groups and networks. Humans tend to be psychological biased toward "influencers" within the group rather than the "bridges" between groups. Just noted some posts from the Facebook company today, no matter how many friends people have on Facebook, people tend to communicatate with same 10-16 people at all times. Not much innovation going on there, I would say.